1. Field of Invention
This invention relates to a grommet. In particular, this invention relates to a grommet that engages around a wire harness to be mounted on a vehicle, such as an automobile, and is mounted in a through hole of an automobile body panel, and improves protection of the wire harness at a position where the wire harness passes through the hole, as well as improving waterproofness and dustproofness.
2. Description of Related Art
Conventionally, a grommet engages around a wire harness to be mounted to extend from an engine compartment to a passenger compartment of an automobile, and the grommet is mounted in a though hole in an automobile body panel that divides the engine compartment from the passenger compartment. Thus, the wire harness passing through the through hole is protected, and intrusion of water, dust and sound from the engine compartment side to the passenger compartment side is prevented.
As the grommet described above, a so-called one motion grommet is provided. When the one motion grommet is simply pressed into the through hole in the automobile body panel from one side to the other, an automobile body engagement recess provided on an outer peripheral surface of the grommet engages with an edge of the through hole.
As shown in FIG. 12, the above-described grommet 1 is provided with a small-diameter tubular portion 2, and a tapered portion 3 which extends from an end of the small-diameter portion 2. The tapered portion 3 is provided with an automobile body engagement recess 4 around a larger diameter end. Both side walls facing each other across a groove 4a of the automobile body engagement recess 4 include a vertical wall 4b at the larger diameter side and an inclined wall 4c at a smaller diameter side. A wire harness W/H is inserted into a hollow portion extending from the small-diameter tubular portion 2 to the tapered portion 3 of the above-described grommet 1, and the grommet 1 is fixed with the wire harness W/H using a tape T at an end of the small-diameter tubular portion.
As shown in FIG. 13, during a mounting operation of the grommet 1 into the through hole R of the automobile body panel P, the grommet 1 is inserted into the through hole R from the small-diameter tubular portion 2, and the inclined wall 4c is pressed inwardly and deformed to pass through the through hole R. Then, the inclined wall 4c, which recovers its original shape after passing through the through hole R, and the vertical wall 4b are tightly pressed into contact with both surfaces of the automobile panel P, respectively. Thus, the automobile body engagement recess 4 of the grommet 1 engages with the through hole R of the automobile body panel P.
However, as shown in FIG. 14, when the one motion grommet 1 is inserted into the through hole R so as to be inclined, one side of the tapered portion 3 is pressed excessively, and thus, an outer peripheral surface of a thin portion of the tapered portion 3, extending to the inclined wall 4c of the automobile body engagement recess 4, is deformed inwardly. The inclined wall 4c, which must bend inwardly, is bent and warped (flipped over) outwardly, and the inclined wall 4c touches the automobile body panel P. Thus, the grommet is prevented from passing through the through hole R.
When the grommet 1 is inserted straight so that the center axis of the grommet 1 is aligned with the center of the through hole R, the above-described problem does not occur. However, during the insertion operation of the grommet 1 into the through hole, it is sometimes difficult to insert the grommet 1 into the through hole straight, because of the restriction on a space. Thus, in many cases, the grommet is inserted in an inclining posture.
Further, if the tapered portion of the grommet 1 is thick so as to be incapable of being bent, the above-described problem is resolved to a certain extent. However, in that case, an insertion force required to insert the grommet into the through hole becomes larger.
Also, during the insertion of the grommet, a largest force to be applied to press the grommet is required before the tapered portion passes through the through hole R. However, since an operator cannot recognize the position where the largest force to be applied is required, the operator tends to apply large force from the beginning, which increases an operational burden.
Accordingly, the present invention is provided in view of the above-described problems. An objective of the present invention is to prevent the insertion force from being too large, and to enable a grommet to be mounted into a through hole of an automobile panel, even if the grommet is inserted in an inclining posture. Another objective of the present invention is to generate tactile sensation so that the operator can recognize the position where the required force to press the grommet into the through hole without stopping is to be applied.
In order to address the problems described above, one aspect of the present invention provides a grommet configured to engage around an outer periphery of a wire harness and to be mounted in a through hole of an automobile body panel. The grommet includes a tubular portion and a tapered portion extending from one end of the tubular portion. The tapered portion includes an automobile body engagement recess provided on an outer peripheral surface of the tapered portion to engage with the automobile body panel. The recess is formed by a first wall provided around the tapered portion at a large-diameter end and a second wall provided around the tapered portion and located at a small-diameter side of the first wall, with the second wall facing the first wall across the automobile body engagement recess. A plurality of projecting strip portions are provided on an outer peripheral surface of the tapered portion. The plurality of outer projecting strip portions extend from an end adjacent the tubular portion toward an edge of the second wall of the recess in an axial direction of the tapered portion and are spaced from each other in a circumferential direction. A plurality of grooves are provided on the outer projecting strip portions, and extend in the circumferential direction. The plurality of grooves are configured to generate tactile sensation when the grommet is mounted into the through hole of the automobile body panel.
The plurality of grooves may be provided in the proximity of the edge of the second wall.
The grommet may have an inclined surface on an outer surface of the plurality of outer projecting strip portions and a substantially planar surface on an outer surface of the plurality of outer projecting strip portions. The substantially planar surface extends from a connecting position to the edge of the second wall in a direction substantially parallel to the axial direction of the tapered portion. The connecting position connects the inclined surface and the substantially planar surface. The plurality of grooves are provided on the substantially planar surface. The plurality of grooves may preferably be provided at a location nearer to the connecting position than to the edge of the second wall.
A projection amount of the plurality of outer projecting strip portions may be changed at a first point and a second point. The first point is located substantially at a position where an outer surface of the plurality of outer projecting strip portions first contacts an inner peripheral surface of the through hole when the grommet is inserted into the through hole from the side of the tubular portion. The second point is located nearer to the edge of the second wall than the first point. An outer surface of the plurality of outer projecting strip portions forms a substantially planar surface that extends between the second point to the edge of the second wall in a direction substantially parallel to the axial direction of the tapered portion. The grooves may be provided on the substantially planar surface. The grooves may be provided at a position nearer to the second point than to the edge of the second wall. The grooves may be provided between the first and second points and disposed at a position close to the second point.
When the outer projecting strip portions are provided on the outer peripheral surface of the grommet, and when the grommet is inserted in an inclining posture, the outer projecting strip portions first touch the inner peripheral surface of the through hole. Accordingly, the operator can recognize the inclined insertion, and reinsert the grommet in a straight manner.
Further, if the outer projecting strip portions are provided on the outer peripheral surface of the tapered portion, when the grommet is inserted in an inclining posture, the phenomenon in which the thin tapered portion extending to the inclined wall of the automobile body engagement recess is warped outwardly (flipped over) at the side contacting the inner peripheral surface of the through hole, does not occur. Accordingly, the problem that occurred at the time of inclined insertion in the conventional grommet can be obviated.
In a further aspect of the present invention, the projecting strip portions are arranged close to each other at the small-diameter side. If the projecting strip portions are arranged close to each other at the small-diameter side, it facilitates the correction of the direction at the time of inclined insertion. When the grommet is inserted in a straight manner, even if the projecting strip portions are arranged close to each other, since they do not contact the inner peripheral surface of the through hole, the inserting force does not increase. On the other hand, since the proportion of the total circumferential area that the outer projecting strip portions take up becomes smaller toward the large-diameter side, the grommet is easily bent in a diameter-reducing direction, and the inserting force can be reduced.
As described above, the grooves for tactile sensation are provided at a front side of the planar surface. Since the planar surface extends at the same height as that of the edge of the second wall, a large insertion force is required. From the position where the inner peripheral surface of the through hole of the automobile body (the inner surface of the burring when the burring projects from the through hole) contacts the groove, the through hole spreads out the groove as it moves. At the position where the through hole-moves over the groove, the groove reacts to recover its original shape, which generates a tactile sensation. Because of the tactile sensation thus generated, the operator can clearly recognize the position where he must apply the strongest pressing force, and thus needs not apply an excessive force from the beginning. Hence, the operator can mount the grommet into the through hole by merely applying the strongest force from the moment he has felt the tactile sensation. This reduces the burden on the operator.
The groove may be located at a position 2 mm-4 mm away from the edge of the second wall. The groove may have a depth extending to a position in the proximity of the outer peripheral surface of the tapered portion, or reaching the outer peripheral surface of the tapered portion, not including the outer projecting strip portions. In other words, the depth of the groove is equal to or less than the distance between upper and lower ends of the outer projecting strip portion. In a preferred embodiment, for example, the depth is about 1 mm.
The groove may have a substantially V-shaped or U-shaped cross section. The groove has an inclination angle xcex81 at a side of the second wall and an inclination angle xcex82 at the side of the tubular portion, relative to an axis extending perpendicularly to the axial direction of the tapered portion and passing through the lowermost bottom of the groove. The inclination angle xcex82 is greater than the inclination angle xcex81.
In other words, the tubular portion side of the groove, which the inner peripheral surface of the through hole (or the inner surface of the burring) contacts first, has a greater angle so that the tubular side of the groove can be easily deformed outwardly. On the other hand, the second wall side of the groove, which the inner peripheral surface of the through hole contacts later, has a smaller angle so that the groove recovers its original shape rapidly after the inner peripheral surface of the through hole moves over the groove.
More specifically, the inclination angle xcex81 satisfies 0xc2x0xe2x89xa6xcex81xe2x89xa630xc2x0, and the inclination angle xcex82 satisfies 0xc2x0xe2x89xa6xcex82xe2x89xa680xc2x0. Of course, the inclination angle xcex82 may not necessarily be greater than the inclination angle xcex81.
The grooves which are to be formed in the substantially planar surface of the outer projecting strip portions are preferably formed on all of the outer projecting strip portions. However, the grooves can be formed only on some of the outer projecting strip portions.
Preferably, a substantially V-shaped or U-shaped recess is provided in an inner peripheral surface of the tapered portion, and is located in the proximity of the second wall. The grooves for tactile sensation are provided on the outer surface of the outer projecting strip portions, and are located in the proximity of the second wall at a position opposite to the recess.
With the above construction, the thickness between the groove of the outer projecting strip portion and the recess of the inner peripheral surface of the tapered portion can be thin. Thus, the insertion force required to move the groove through the inner peripheral surface of the through hole can be reduced.
A sunken portion may be formed on the outer peripheral surface of the tapered portion between adjacent outer projecting strip portions. The sunken portion has at least one channel that extends in the axial direction and a first substantially planar surface that connects to the edge the edge of the second wall. The outer projecting strip portions include a second substantially planar surface that connects to the edge the edge of the second wall. The first and second substantially planar surfaces form a substantially coplanar surface at the side of the edge of the second wall. The substantially coplanar surface is continuous in the circumferential direction. The second substantially planar surface has a region that extends further toward the tubular portion than the first substantially planar surface. The grooves for tactile sensation are provided in the extended region.
As described above, since the substantially coplanar surface is provided at the edge of the second wall continuously in the circumferential direction, the grommet can be more fixedly secured in the through hole. Further, since the grooves are provided in the extended region that reaches further toward the tubular portion than the substantially planar surface of the sunken portion, the grooves can be easily deformed, thereby generating a stronger tactile sensation.
If a channel is provided in the sunken portion between adjacent outer projecting strip portions that extend in the axial direction, the grommet becomes easy to bend circumferentially since the portion of the groove is thinned. Accordingly, even if the grommet is inserted in an inclining posture and is hooked by the inner peripheral surface of the through hole, the grommet is bent circumferentially and the inserting posture is easily corrected. Further, when the outer surface of the projecting strip portions contacts the inner peripheral surface of the through hole, the tapered portion is easily bent inwardly about the groove, and the grommet is deformed in the diameter-reducing direction.
The channel can be a single center channel provided at the center of the sunken portion, or can be two side channels provided along the proximal portions of the projecting strip portions. It is possible to provide both the center channel and the two side channels. In this case, preferably, both side channels extend to the end of the second wall and the center channel extends only to the periphery of the end of the second wall, i.e., is shorter than the side channels.
As described above, if the single center groove is provided at the center of the triangle sunken portion, the grommet is easily bent about the center groove. Further, if the groove is provided along the proximal portion of the projecting strip portion, the proximal portion of the projecting strip portion is easily bent. Further, if both the single center groove and the two side grooves along the proximal portions are provided, the ease of bending is doubled.
In addition, the grooves for tactile sensation may be provided on an inclined surface connecting to the substantially planar surface, at a position close to the substantially planar surface, in the situation where the substantially planar surface is shorter.
The grommet of the present invention further has an end face portion provided at an end of a large-diameter side of the tapered portion, and a second tubular portion extending outwardly from the center of the end face portion. The second tubular portion is configured to receive at least one fixing element that fixes the second tubular portion to the wire harness. The end face has a greater thickness than the tapered portion not including the outer projecting strip portions.
As described above, since the thickness of the end face is great, even if a pulling force from the wire harness acts on the grommet through the second tubular portion, deformation of the grommet can be prevented, thereby generating a resisting force against the direction of the separation of the grommet from the through hole of the automobile body.
In another aspect of the present invention, a grommet configured to engage around an outer periphery of a wire harness and to be mounted in a through hole of an automobile body panel is provided. The grommet has a tubular portion and a tapered portion extending from one end of the tubular portion. An automobile body engagement recess is provided on an outer peripheral surface of the tapered portion to engage with the automobile body panel. A plurality of outer projecting strip portions are provided on an outer peripheral surface of the tapered portion. The plurality of outer projecting strip portions extend from an end adjacent the tubular portion toward the engagement recess in an axial direction of the tapered portion and are spaced from each other in a circumferential direction. A plurality of grooves are provided on the outer projecting strip portions, and extend in the circumferential direction. The plurality of grooves are provided in the proximity of the engagement recess so that the grooves generate tactile sensation prior to completion of the mounting of the grommet into the through hole of the automobile body panel.
An insertion facilitating recess may be provided in an inner peripheral surface of the tapered portion, preferably in the proximity of the engagement recess. The grooves for tactile sensation are provided on the outer projecting strip portions in the proximity of the engagement recess at a position opposite to the insertion facilitating recess.
In a further aspect of the present invention, a grommet configured to engage around an outer periphery of a wire harness and to be mounted in a through hole of an automobile body panel is provided. The grommet includes a tubular portion and a tapered portion extending from one end of the tubular portion. An automobile body engagement recess is provided on an outer peripheral surface of the tapered portion to engage with the automobile body panel. The recess is formed by a first wall provided around the tapered portion at a large-diameter end and a second wall provided around the tapered portion and located at a small-diameter side of the first wall. The second wall faces the first wall across the recess. A plurality of outer projecting strip portions are provided on an outer peripheral surface of the tapered portion. The plurality of outer projecting strip portions extend in an axial direction of the tapered portion and are spaced from each other in a circumferential direction. The plurality-of the outer projecting strip portions are arranged close to each other at a small-diameter end of the tapered portion and are radially spread apart toward a large-diameter end. The outer projecting strip portions are bent at a first point and a second point. The first point is located substantially at a position where an outer surface of the plurality of outer projecting strip portions first contacts an inner peripheral surface of the through hole when the grommet is inserted into the through hole from the side of the tubular portion. The second point is located nearer to the edge of the second wall than the first point. Formed on an outer surface of the plurality of outer projecting strip portions is a substantially planar surface that extends from the second point to an edge of the second wall in a direction substantially parallel to the axial direction. A plurality of grooves are provided on the substantially planar surface and extend in the circumferential direction. The plurality of grooves are configured to generate tactile sensation when the grommet is mounted into the through hole of the automobile body panel.
The grooves for tactile sensation may be provided at a position nearer to the second point than to the edge of the second wall. The substantially planar surface may be located at the same height as the edge of the second wall.